/********************************************************
 * Xpress-BCL Java Example Problems
 * ================================
 *
 * file xbburgi.java
 * `````````````````
 * Burglar problem.
 * Binary variable formulation with index sets.
 *
 * (c) 2008-2024 Fair Isaac Corporation
 * author: S.Heipcke, Jan. 2000, rev. Mar. 2011
 ********************************************************/

import com.dashoptimization.*;

public class xbburgi {
  /****DATA****/
  /* Item:                          ca  ne  va  pi  tv  vi  ch  br */
  static final double[] VALUE = {15, 100, 90, 60, 40, 15, 10, 1};

  /* Value of items */
  static final double[] WEIGHT = {2, 20, 20, 30, 40, 30, 60, 10};
  /* Weight of items */
  static final double WTMAX = 102; /* Max weight allowed for haul */

  static final String[] ITEMNAMES = {
    "camera", "necklace", "vase", "picture",
    "tv", "video", "chest", "brick"
  };

  static int NItems; /* Number of items */

  public static void main(String[] args) {
    try (XPRBprob p = new XPRBprob("Burglari"); /* Initialize BCL and create a new problem */
        XPRBexprContext context =
            new XPRBexprContext() /* Release XPRBexpr instances at end of block. */) {
      XPRBvar[] x;
      XPRBindexSet ITEMS; /* Set of items */
      int i;
      XPRBexpr lobj, kn;

      /****INDICES****/
      ITEMS = p.newIndexSet("Items", ITEMNAMES.length); /* Create the index set */
      for (i = 0; i < ITEMNAMES.length; i++) ITEMS.addElement(ITEMNAMES[i]);

      NItems = ITEMS.getSize(); /* Get the size of the index set */

      /****VARIABLES****/
      x = new XPRBvar[NItems];
      for (i = 0; i < NItems; i++) x[i] = p.newVar("x_" + ITEMS.getIndexName(i), XPRB.BV);
      /* 1 if we take item i; 0 otherwise */

      /****OBJECTIVE****/
      lobj = new XPRBexpr();
      for (i = 0; i < NItems; i++) lobj.add(x[i].mul(VALUE[i]));
      p.setObj(lobj); /* Set objective: maximize total value */

      /****CONSTRAINTS****/
      kn = new XPRBexpr();
      for (i = 0; i < NItems; i++) kn.add(x[i].mul(WEIGHT[i]));
      p.newCtr("WtMax", kn.lEql(WTMAX)); /* Weight restriction */

      /****SOLVING + OUTPUT****/
      p.setSense(XPRB.MAXIM); /* Choose the sense of the optimization */
      p.mipOptimize(""); /* Solve the MIP-problem */
      System.out.println("Objective: " + p.getObjVal()); /* Get objective value */

      for (i = 0; i < NItems; i++) /* Print out the chosen items */
        if (x[i].getSol() > 0) System.out.println(ITEMS.getIndexName(i) + ": " + x[i].getSol());
    }
  }
}